Main content

## Class 10 (Old)

### Course: Class 10 (Old) > Unit 12

Lesson 3: Frustum of a cone# Curved surface area of a frustum

Let's learn how to find the curved surface area of a frustum of a cone through an example. Let's use the intuitive approach rather than directly plugging into the formula. Created by Aanand Srinivas.

## Want to join the conversation?

- where did he get the 22/7 from?(0 votes)
- it's a value of pi(1 vote)

- how did h1 = 8cm.

this was not clear how you completed the calculation(0 votes)- He arrives to h1/h1+4 = 6/9 because of proportionality.

He then cross multiplies and arrives at 9h1 = 6h1+24

That can be rearranged into 9h1-6h1=24.

3h1=24

Then we divide both sides by 3

3h1/3=24/3

h1=8(0 votes)

- In a certain group members were contributing 2000000 total,if 40 of the members pulled out the remaining members had to contribute 2500 more.How many members were there in the group(0 votes)